1. Field of the Invention
This invention relates to an ink jet recording apparatus, and more particularly to an ink jet recording apparatus having a function for automatically changing a mode of recording operation to fit to a newly installed interchangeable recording head unit in an extremely simple and low cost structure.
This invention also relates to an interchangeable recording head unit.
This invention also relates to a method of performing the above-mentioned function.
2. Discussion of the Background
Ink jet type recording has been widely adapted to various types of data outputting apparatus, such as a printer connected to a digital processing system, a facsimile apparatus, a copying apparatus, and so forth. A reason is that ink jet recording apparatus produces vibrations and acoustic noises both at minimal levels during a recording operation, in comparison with other type of data outputting apparatus. Another reason, which is considered as an increasingly important factor for data outputting apparatus by the recent demand, is that the ink jet recording apparatus can easily handle colors.
The ink jet recording apparatus has a recording head unit which includes an ink cartridge and an ink jet head operated by an actuating element, such as, a piezoelectric element, an exothermic reaction resisting element, or the like. By driving such an actuating element in accordance with a signal to be recorded, ink in the ink cartridge is discharged through nozzles and falls onto a recording medium. As a result, an image is recorded on a recording medium.
Recording head units for use with a particular ink jet recording apparatus are provided as combinations of an ink cartridge and an ink jet head, and are interchangeable with each other in the apparatus. This type of recording head unit (i.e., interchangeable) has been developed in order to help users in the case, for example, when an amount of ink in the ink cartridge remaining is small, or when an image quality deteriorates owing to an abnormal operation of the ink jet head.
When the above-mentioned interchangeable recording head unit is replaced in the recording apparatus at the user's convenience, the replacement recording head unit may have recording characteristics, such as number of ink jet nozzles, recording density, and also ink discharging efficiency, which differ from the previously installed recording head unit. Particularly, the ink discharging efficiency may be variable due to the fabrication dispersion when the recording head units are manufactured. In this case, the background ink jet recording apparatus may reduce its image quality level. In order to avoid this problem and to assure the quality performance, two countermeasures are required. One countermeasure is to reduce the variation of ink discharging efficiency to the point where it does not create a problem of image quality deterioration. This countermeasure can be achieved by selecting a recording head unit which has an ink discharging efficiency within a predetermined range. The other countermeasure is that the ink jet recording apparatus is provided with a function for detecting differences of ink jet head characteristics and for accordingly changing a mode of recording operation.
In addition, in some cases, a recording head unit may consist of a ink jet head, and an ink cartridge may be provided separately from the recording head unit. This type of recording head unit has also been made interchangeable. The reason is that a function of an interchangeable recording head unit is important for users, particularly, when the user desires to switch recording head units from one to the other in order to change a mode of recording operation, such as, a full-color recording or a black and white recording, a high recording density or a low recording density, and so forth.
The ink jet recording apparatus disclosed in the Japanese Laid Open Patent Application 61-197247 (1986) has a recording head unit which includes a head driving voltage setting circuit in an electrical interface circuit board of the recording head unit.
However, in this case, the interface circuit becomes a relatively complex and high cost structure. In addition, a procedure of setting a head driving voltage is highly complicated.
Presently, there is no ink jet recording apparatus which has a function of automatically changing a mode of recording operations to fit to a newly installed recording head unit in an extremely simple and low cost structure.